While not directly related to the present invention, PTL 1 and 2 have been detected by prior art search. PTL 1 discloses a congestion monitoring system that monitors a congestion state about data transmission among a plurality of devices. At least one of the devices includes a back pressure information generation means generating back pressure information for instructing an preceding device to stop or continue data transmission based on a result of comparison between the amount of unprocessed data retained and a predetermined threshold. A device, located upstream of the device including the back pressure information generation means includes: a data transmission stopping means that stops data transmission based on content of the back pressure information; a monitoring means that monitors change in the back pressure information transmitted from the corresponding back pressure information generation means to the data transmission stopping means along with a lapse of time; and an index calculating means that calculates an index indicating a back pressure occurrence frequency based on information obtained by monitoring by the corresponding monitoring means. With the congestion monitoring system, an index that indicates urgency about the congestion state can be calculated in real time.
PTL 2 discloses a configuration including: an external RAM token counter holding token values obtained by adding token values of meter IDs of a plurality of users; and first and second information caches extracting a meter ID and length information about each packet data and storing packet information including a coincidence flag representing the sameness among meter IDs and lengths of a predetermined number of packets and a predetermined number of meter IDs. A timing generation unit is used for a switch operation so that one of the first and second information caches receives packet information and the other information cache performs token calculation with a token calculation unit on each meter ID. This configuration also includes first and second information buffers in which a flag representing passage/discard of packet data is set as a calculation result.